Provision of drugs and other medical treatments has been usually by injection, pills, and nasal sprays; more recently transdermal patches have been used to deliver a measured amount of the drug or other treatment concerned. In this specification “treatment” includes pre-treatments of persons to minimise their risk of reaction if subsequently exposed, for example, to hazardous gases.
There remains, however, an issue in ensuring the accuracy of delivery of the drug or other treatment concerned in some circumstances. In the case of transdermal treatments with patches, it is difficult to ensure the patch continues to adhere sufficiently to enable the drug or other treatment to cross the skin barrier for a long enough time for the treatment to be effective.
A small number of drugs are available in spray-on formulations, but these require significant dexterity to apply and give very inconsistent doses due to variation in the accuracy of the user, the distance of the spray from the target and the number of times and force with which the nozzle is pressed.